/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Collections;
using System.Reflection;
using Microsoft.Extensions.Logging;
using Spring.Aop;
using Spring.Caching;
using Spring.Util;

namespace Spring.Aspects.Cache;

/// <summary>
/// Implementation of a parameter caching advice.
/// </summary>
/// <remarks>
/// <p>
/// This advice can be used to cache the parameter of the method.
/// </p>
/// <p>
/// Information that determines where, how and for how long the return value
/// will be cached are retrieved from the <see cref="CacheParameterAttribute"/>s
/// that are defined on the pointcut.
/// </p>
/// <p>
/// Parameter values are cached *after* the target method is invoked in order to
/// capture any parameter state changes it might make (for example, it is common
/// to set an object identifier within the save method for the persistent entity).
/// </p>
/// </remarks>
/// <seealso cref="CacheParameterAttribute"/>
/// <author>Aleksandar Seovic</author>
public class CacheParameterAdvice : BaseCacheAdvice, IAfterReturningAdvice
{
    private class CacheParameterInfo
    {
        public readonly ParameterInfo[] Parameters;
        public readonly CacheParameterAttribute[][] CacheParameterAttributes;

        public CacheParameterInfo(ParameterInfo[] parameters, CacheParameterAttribute[][] cacheParameterAttributes)
        {
            Parameters = parameters;
            CacheParameterAttributes = cacheParameterAttributes;
        }
    }

    private readonly Hashtable _cacheParameterInfoCache = new Hashtable();

    private CacheParameterInfo GetCacheParameterInfo(MethodInfo method)
    {
        CacheParameterInfo cpi = (CacheParameterInfo) _cacheParameterInfoCache[method];
        if (cpi == null)
        {
            ParameterInfo[] parameters = method.GetParameters();
            CacheParameterAttribute[][] parameterInfos = new CacheParameterAttribute[parameters.Length][];
            for (int i = 0; i < parameters.Length; i++)
            {
                ParameterInfo p = parameters[i];
                CacheParameterAttribute[] paramInfoArray = (CacheParameterAttribute[]) GetCustomAttributes(p, typeof(CacheParameterAttribute));
                parameterInfos[i] = paramInfoArray;
            }

            cpi = new CacheParameterInfo(parameters, parameterInfos);
            _cacheParameterInfoCache[method] = cpi;
        }

        return cpi;
    }

    /// <summary>
    /// Executes after target <paramref name="method"/>
    /// returns <b>successfully</b>.
    /// </summary>
    /// <remarks>
    /// <p>
    /// Note that the supplied <paramref name="returnValue"/> <b>cannot</b>
    /// be changed by this type of advice... use the around advice type
    /// (<see cref="AopAlliance.Intercept.IMethodInterceptor"/>) if you
    /// need to change the return value of an advised method invocation.
    /// The data encapsulated by the supplied <paramref name="returnValue"/>
    /// can of course be modified though.
    /// </p>
    /// </remarks>
    /// <param name="returnValue">
    /// The value returned by the <paramref name="target"/>.
    /// </param>
    /// <param name="method">The intecepted method.</param>
    /// <param name="arguments">The intercepted method's arguments.</param>
    /// <param name="target">The target object.</param>
    /// <seealso cref="AopAlliance.Intercept.IMethodInterceptor.Invoke"/>
    public void AfterReturning(object returnValue, MethodInfo method, object[] arguments, object target)
    {
        bool isLogDebugEnabled = logger.IsEnabled(LogLevel.Debug);

        CacheParameterInfo cpi = GetCacheParameterInfo(method);
        CacheParameterAttribute[][] cacheParameterAttributes = cpi.CacheParameterAttributes;

        if (cacheParameterAttributes.Length > 0)
        {
            IDictionary<string, object> vars = PrepareVariables(method, arguments);
            for (int i = 0; i < cacheParameterAttributes.Length; i++)
            {
                foreach (CacheParameterAttribute paramInfo in cacheParameterAttributes[i])
                {
                    AssertUtils.ArgumentNotNull(paramInfo.KeyExpression, "Key",
                        "The cache attribute is missing the key definition.");

                    if (EvalCondition(paramInfo.Condition, paramInfo.ConditionExpression, arguments[i], vars))
                    {
                        ICache cache = GetCache(paramInfo.CacheName);

                        object key = paramInfo.KeyExpression.GetValue(arguments[i], vars);

                        if (isLogDebugEnabled)
                        {
                            logger.LogDebug(string.Format("Caching parameter for key [{0}] into cache [{1}].", key, paramInfo.CacheName));
                        }

                        cache.Insert(key, arguments[i], paramInfo.TimeToLiveTimeSpan);
                    }
                }
            }
        }
    }
}
